Flashcards in Tumors of the CNS Deck (30):
Most frequent primary tumor of the CNS
Risk factors for CNS tumors
- ionizing radiation
- genetic syndromes
Do we need to know all of these hereditary syndromes assoc with brain cancer?
Cerebreal perfusion pressure is the difference between
MAP and intracranial pressure. Intracranial pressure remains fairly constant until the brain compliance threshold is reached. Then small increases in the size of a tumor can lead to large increases in intracranial pressure and thus drive down cerebral perfusion
General signs and symptoms of CNS tumors
mental status change
Focal signs and symptoms
focal neuro deficits
Stop at 17
herniation of the cingulate gyrus under the falx cerebri.
May compress anterior cerebral artery and CVA
Diencephalic downward herniation
- may cause drowsiness, impaired vertical gaze or small pupils bilaterally
ipsilateral oculomotor nerve palsy and contra or ipsilateral hemiparesis
Upward herniation through tentorium
may cause ipsilateral oculomotor, horner, and contralateral hemiparesis
causes BP changes, weakness, respiratory disturbance, horner syndrome
T1 weighted MRI scan
Water is hypointense (dark); ie tumor, swelling, CSF darker than surrounding brain
Injected contrast that leaks across the disrupted BBB appears hyperintense with an increased signal or brighter than the surrounding brain.
T2 weighted MRI scan
CSF Edema and tumors appear hyperintense.
What does Glioma mean?
tumor derived from glial cells
Most common primary CNS tumors are gliomas, of glial origin
Low grade tumors most commonly seen in
High Grade Tumors more commonly seen in
those older than 50
Low grade tumor characteristics
well differentiated, show no nuclear atypia, and have low mitotic index.
Increasing de-differentiation, higher mitotic index, vascular proliferation, and necrosis determine higher tumor grade.
How many tumor grades are there
- conventional: no longer used
- conformal: tumor gets more dose while normal brain dose is reduced
- radiosurgery: high dose of conformal radiation given in a single fraction
- brachytherapy: insertion of radioactive material in tumor cavity
What is bad about conventional radiation
tumor tissue and normal tissue receive the same dose
outside of the brain (extra-axial) tumors characterized on MRI by diffuse enhancement and a DURAL TAIL.
Generally benign and resectable
May show seizures or focal signs due to brainstem compression. Remember that it is the second most common primary brain tumor
3rd most common primary brain tumor
Classifications of pituitary tumors
- Microadenomas: most often hrmone secreting
- Macroadenomas: most often do not secrete hormones, often grow large enough to cause sompression and hypofunction of gland or pituitary stalkP
Pituitary tumors often compress what?
Acoustic neuroma also called
vestibular schwannoma- benign tumor of schwann cells surrounding CN VIII
- Benign slow growing tumors that often present with hearing loss, tinnitus, headache, dizziness, facial numbness or weakness
- treatment= observation, surgical excision, excellent outcome with experienced neurosurgeon
Primary CNS lymphoma
on the rise, due to malignant transformation on trafficking B lymphocytes. Highly chemo and radiosensitive tumor.